Java APIs

First, define a probe (an instance of the entity class): User user = new User();user.setName(“Ana”);user.setEmail(“[email protected]”); Next create a probe: Example userExample = Example.of(user); Next, define a repository that extends QueryByExampleExecutor interface: @Repository public interface UserRepository extends JpaRepository, QueryByExampleExecutor { } Finally, call one of the QueryByExampleExecutor methods (e.g., exists()): public

The JDK 11 HttpClient API is very flexible and intuitive. Here it is a sample of triggering a GET request and printing the response: HttpClient client = HttpClient.newHttpClient();HttpRequest request = HttpRequest.newBuilder() .uri(URI.create(“https://reqres.in/api/users/4”)) .build();HttpResponse response= client.send(request, BodyHandlers.ofString());System.out.println(“Status code: ” + response.statusCode());System.out.println(” Body: ” + response.body());

Via Java Reflection API, we can obtain all the annotations of a class as follows: Class clazz = Foo.class;Annotation[] clazzAnnotations = clazz.getAnnotations();

Java has an API called BigInteger and it is easily able to identify if the number under consideration is a prime number or not. Code snippet: import java.math.BigInteger;public class ProbablePrime{ public static void main(String[] args) { ProbablePrime probablePrime = new ProbablePrime(); int numberArg = Integer.parseInt(args[0]); probablePrime.proceed(numberArg); } private void proceed(int

You may want to know if your timezone supports Daylight Saving Time programmatically. This can be easily determined with the code below: Listing 1. Sample Code import java.util.TimeZone;public class DaylightSavingsTime{ public static void main(String args[]) { DaylightSavingsTime daylightSavingsTime = new DaylightSavingsTime(); daylightSavingsTime.proceed(); } private void proceed() { TimeZone tz =